Scanning tunneling spectroscopy is used to study the energy dependence of wavevectors of the local‐density‐of‐states (LDOS) modulations in near‐optimal Bi2Sr2CaCu2O8+&dgr;. Atomic‐resolution energy‐resolved spectroscopic images are acquired in a 650 Å field of view on the BiO cleave surface of these crystals at 4.2K. Fourier transformations are then used to determine the wavevectors of any spatial modulation in theLDOS. At sub‐gap energies, up to 16 inequivalent sets of dispersive wavevectors are observed. When analyzed within a model of quasiparticle scattering‐induced interference between a characteristic ‘octet’ of states in momentum‐space, they yield an estimate of the Fermi‐surface location and the energy gap |&Dgr;(k)| in good agreement with ARPES. At energies approaching the gap‐maximum, theLDOSmodulations become intense, commensurate with the crystal, and localized by the apparent nanoscale domains. This may indicate that the lifetimes of thek&vec;= (&pgr; /a0,0) quasiparticles, which are central to high‐Tcsuperconductivity, are determined by nanoscale disorder scattering. © 2003 American Institute of Physics